Tuberculosis

What is tuberculosis?

Tuberculosis is a bacterial disease usually affecting the lungs (pulmonary TB) caused by Mycobacterium tuberculosis. Other parts of the body (extrapulmonary TB) can also be affected; for example brain, lymph nodes, kidneys, bones, joints, larynx, intestines or eyes.

Who gets tuberculosis?

Tuberculosis can affect people of any age. Most often, it is associated with older people who have had previous tuberculosis exposure. Individuals with weakened immune systems including those with AIDS or those infected with the human immunodeficiency virus (HIV) are at increased risk.

How is tuberculosis spread?

The bacteria causing tuberculosis is spread through the air. When a person with tuberculosis, who is not taking tuberculosis medication, coughs or sneezes, the germs get into the air. Prolonged exposure to the tuberculosis bacteria is normally necessary for infection to occur.

What is the difference between tuberculosis infection and tuberculosis disease?

Tuberculosis infection may result after close contact with a person who has tuberculosis disease. Tuberculosis infection is determined by a significant reaction to the Mantoux skin test with no symptoms of tuberculosis, and no TB bacteria found in the sputum. Tuberculosis disease is characterized by the appearance of symptoms, a significant reaction to a Mantoux skin test and TB bacteria found in the sputum.

To spread the TB bacteria, a person must have TB disease. Having TB infection is not enough to spread the bacteria. Tuberculosis may last for a lifetime as an infection, never developing into disease. However, individuals with TB infection are at considerable risk of developing TB disease, particularly during the first year after acquiring the infection. Additionally, individuals with weakened immune systems such as persons infected with HIV, are at high risk of developing TB disease if TB infection is untreated.

What are the symptoms of tuberculosis?

The symptoms of TB include a low-grade fever, nightsweats, fatigue, weight loss and a persistent cough. Some people may not have obvious symptoms.

How soon do symptoms appear?

Evidence of infection (a positive skin test) may occur from four to 12 weeks after exposure. The most hazardous period for developing clinical disease is usually within 6 to 12 months after infection, but can be latent, occurring much later in life.

When and for how long is a person able to spread tuberculosis?

A person with TB disease may remain contagious until he/she has been on appropriate treatment for several weeks. It is important to note that a person with TB infection, but not disease, cannot spread the infection to others, since there are no TB bacteria in the sputum.

What is the treatment for tuberculosis?

People with active TB disease must complete the prescribed course of medicine, which usually involves taking isoniazid (INH) for 6 to 12 months. TB infection is treated with isoniazid alone; treatment of TB disease usually requires three or more drugs. The exact medication plan must be determined by a physician.

What can be the effect of not being treated for tuberculosis?

In addition to spreading the disease to others, an untreated person may become severely ill or die.

What can be done to prevent the spread of tuberculosis?

The most important way to stop the spread of tuberculosis is to cover the mouth and nose when coughing, and to take the prescribed medicine as directed. Persons with disease should be excluded from school, daycare or the workplace until the sputum is negative (about 2-4 weeks after the beginning of treatment). All household and close contacts of a person with active TB disease should be screened using the Mantoux skin test for evidence of infection. All contacts with evidence of infection, should be treated with INH. All high risk populations should be TB skin tested routinely.

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.